Heat sink with vapor chamber

ABSTRACT

A heat sink includes a tank and a plate covering on the tank and hermetically engaging with the tank. The tank includes a base for absorbing heat from heat-generating members and a sintered wick layer formed at an inner face of base. The plate has a meshed wick layer formed at an inner face thereof. A chamber is defined between the tank and the plate and contains working fluid therein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink with vapor chamber, and more particularly to a heat sink with vapor chamber having wick structure.

2. Description of Related Art

It is well known that heat is generated during operations of electronic components, such as integrated circuit chips. To ensure normal and safe operations, cooling devices such as heat sinks are often employed to dissipate the generated heat away from these electronic components.

As progress continues to be made in the electronics art, more components on the same real estate generate more heat. The heat sinks used to cool these chips are accordingly made larger in order to possess a higher heat removal capacity, which causes the heat sinks to have a much larger footprint than the chips. Generally speaking, a heat sink is more effective when there is a uniform heat flux applied over an entire base of the heat sink. When a heat sink with a large base is attached to an integrated circuit chip with a much smaller contact area, there is significant resistance to the flow of heat to the other portions of the heat sink base which are not in direct contact with the chip.

A mechanism for overcoming the resistance to heat flow in a heat sink base is to attach a heat spreader to the heat sink base or directly make the heat sink base as a heat spreader. Typically, the heat spreader includes a vacuum chamber defined therein, a wick structure provided in the chamber and lining an inside wall of the chamber, and a working fluid contained in chamber. As an integrated circuit chip is maintained in thermal contact with the heat spreader, the working fluid contained in the wick structure corresponding to a hot contacting location vaporizes. The vapor then spreads to fill the chamber, and wherever the vapor comes into contact with a cooler surface of the chamber, it releases its latent heat of vaporization and condenses. The condensate returns to the hot contacting location via a capillary force generated by the wick structure. Thereafter, the condensate frequently vaporizes and condenses to form a circulation to thereby remove the heat generated by the chip.

Conventionally, the wick structure of the heat spreader is a meshed or sintered type. Generally, the messed wick structure has advantage of good osmosis, but drawbacks of bad heat transferring capacity and weak gravity resistance. While the sintered wick structure has advantages of good heat transferring capacity and gravity resistance, but drawback of large hydro-resistance. Therefore, heat spreaders with single meshed wick structure or sintered wick structure does not achieve a perfect heat dissipation efficiency for the aforesaid chips.

What is needed therefore is to provide a heat sink with vapor chamber having wick structures which achieves good heat dissipation performance.

SUMMARY OF THE INVENTION

A heat sink in accordance with a preferred embodiment of the present invention comprises a tank and a plate covering on the tank and hermetically engaging with the tank. The tank comprises a base for absorbing heat from heat-generating members and a sintered wick layer formed at an inner face of base. The plate has a meshed wick layer formed at an inner face thereof. The sintered wick layer and the meshed wick layer are in porosity communication. A chamber is defined between the tank and the plate and contains working fluid therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present heat sink with vapor chamber can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present portable projector using a related heat dissipation system. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is an isometric, exploded view of a heat sink in accordance with a preferred embodiment of the present invention;

FIG. 2 is an assembled view of FIG. 1;

FIG. 3 is an inverted view of FIG. 2;

FIG. 4 is a sectional view of FIG. 2 taking along a line IV-IV; and

FIG. 5 is an enlarged view of a part V shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, the heat sink comprises a heat spreader 10 and a plurality of fins 30 arranged on the heat spreader 10.

Referring also to FIGS. 3-5, the heat spreader 10 comprises a tank 110 and a top plate 150 hermetically covering on the tank 110, thereby defining a chamber 180 between the tank 110 and the plate 150. The tank 110 comprises a cuboids body 111 and a flange 112 circumferentially extending outwardly from the body 111. The body 111 comprises a heat absorbing base 113 and four interconnecting sidewalls 114 integrally extending upwardly from the base 113. A sintered wick layer 116 is formed on an inner face of the body 111 by sintering metal power at the inner face. The sintered wick layer 116 covers allover the inner face, that is to say, the sintered wick layer 116 covers the base 113 and the sidewalls 114 of the tank 110. A meshed wick layer 156 is formed on an inner face of the plate 150 by tightly engaging a mesh sheet to the inner face. The sintered wick layer 116 on the sidewalls 114 extends toward the plate 150 to engage with the meshed wick layer 156. The sintered wick layer 116 and the meshed wick layer 156 are in porosity communication, therefore, liquid can flows between the sintered wick layer 116 and the meshed wick layer 156. The plate 150 has edges thereof air-tightly and liquid-tightly engaging with the flange 112 of the tank 110. Working fluid is filled in the chamber 180.

Each fin 30 is made from metal sheet. The fin 30 is substantially L-shaped, and comprises a contacting portion (not labeled) thermally contacting the plate 150 of the heat spreader 10 and a heat dissipation portion (not labeled) extending remote from the plate 150.

In use, the base 113 of the tank 110 of the heat spreader 10 thermally contacts and absorbs heat from a heat-generating chip. The working fluid in the chamber 180 of the tank 110 is heated and vapored upwardly to reach the plate 150 of the heat spreader 10. At the plate 150, the vapored working fluid exchanges heat with the plate 150 and then is condensed to liquid. The liquid refluences to the base 113 via the meshed wick layer 156 and the sintered wick layer 116. The vapored and condensed cycle continues, the heat generated by the chip is transferred to the plate 150, and the heat in the plate 150 is dissipated by the fins 30 on the plate 150.

According to the embodiment of the present invention, the heat spreader 10 of the heat sink comprises two different wick layers located at different locations thereof: the sintered wick layer 116 at the base 113 which absorbs heat from the heat-generating chip, the meshed wick layer 156 at the plate 150 which releases heat to other members. Therefore, the heat generated by the chip can be absorbed quickly by the base 113 and the working fluid, then reaches the plate 150 to be dissipated. The working fluid refluences to the base 113 rapidly via the meshed wick layer 156 and the sintered wick layer 116.

It is believed that the present invention and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention. 

1. A heat sink comprising: a tank comprising a base for absorbing heat from a heat-generating member, and a sintered wick layer formed at an inner face of base; a plate covering on the tank and hermetically engaging with the tank, the plate having a meshed wick layer formed at an inner face thereof; and a chamber being defined between the tank and the plate, the chamber containing working fluid therein.
 2. The heat sink of claim 1, wherein the sintered wick layer and the meshed wick layer are in porosity communication.
 3. The heat sink of claim 1, wherein the tank comprises sidewalls extending from the base, the sintered wick layer covering inner faces of the sidewalls.
 4. The heat sink of claim 3, wherein the sintered wick layer covers allover the base and the sidewalls.
 5. The heat sink of claim 3, wherein the tank comprises a flange extending from the sidewalls, the flange engaging with the plate.
 6. The heat sink of claim 5, wherein the flange parallels to the plate.
 7. The heat sink of claim 1 further comprising a plurality of fins, wherein the fins thermally contacts the plate.
 8. The heat sink of claim 7, wherein each of the fins is L-shaped.
 9. The heat sink of claim 8, wherein each of the fins comprises a contacting portion thermally contacting the plate and a heat dissipating portion extending remote from the plate.
 10. A heat sink comprising: a tank containing phase-changeable working fluid therein; a plate hermetically covering the tank; a first wick layer lining to tank; and a second wick layer lining to the plate, the second wick layer being different from the first wick layer and in porosity communication with the first wick layer.
 11. The heat sink of claim 10, wherein the tank comprises a heat absorbing base and a sidewall extending from the base.
 12. The heat sink of claim 11, wherein the first wick layer covers the sidewall and the base.
 13. The heat sink of claim 10, wherein the tank extends a flange engaging with the plate.
 14. The heat sink of claim 13, wherein the flange parallels to the plate.
 15. The heat sink of claim 10 further comprising a plurality of fins positioned on the plate. 